To demonstrate that data from the Stroke and Traumatic Coma Data Banks are reliable, studies of inter-observer agreement have been implemented. These studies include a pilot study of agreement among CT Scan readers in the pilot Traumatic Coma Data Bank, and studies of variations in neurological examination, diagnosis and CT scan reading for the Stroke Data Bank. Four studies have been initiated to date. A study of CT measurements is being planned for the Coma Data Bank. a manuscript on observer agreement in stroke diagnosis have been written and is being submitted for publication. A manuscript on observer agreement in CT readings of stroke anatomy is in preparation.